We examined differences in microhabitat use between Boreal (Poecile hudsonicus) and Black-capped chickadees (P. atricapillus) where they co-occur near Marquette, Michigan, USA. Twenty-four Boreal and 37 Black-capped chickadees were followed during 60 hrs of field observation. Boreal Chickadees foraged only in three conifer species, 76% of which were black spruce ...

Red-tailed Hawks (Buteo jamaicensis) usually hunt from a perch and
swoop down on prey. I observed a novel foraging strategy in which the
bird deliberately, and successfully, attacked and deconstructed nests of
squirrels to flush or capture prey in an urban environment.

The Tody Motmot (Hylomanes momotula) has a fragmented range throughout Central America. I present evidence from audio recordings for a new location for this species in Costa Rica. Individuals detected likely represent a previously undiscovered population in the foothills of the Caribbean Slope of the Tilaran Mountains. A small population ...

Inter- and intra-specific competition are known to influence feeding decisions, but relatively little research has investigated how inter- and intrasexual interactions can impact foraging. We studied foraging preferences of male and female Northern Cardinals (Cardinalis cardinalis) during winter and found they preferred sunflower seed to safflower seed when presented with ...

Previous Chimney Swift (Chaetura pelagica) trapping efforts relied on chimney-top box traps at large roost sites, which were disruptive and inefficient when targeting individual birds. I designed a hoop net for use at nest chimneys to trap individual breeding birds. I caught 13 swifts at 11 different sites in Guelph, ...

Relocation by dependent young is a survival strategy that occurs among a wide range of taxa. The Common Nighthawk (Chordeiles minor) lays its eggs on bare substrate and, once hatched, nestlings may relocate to new sites daily. We located and monitored eight Common Nighthawk nests in Grand Teton National Park, ...

Hematocrit, the percentage of packed red blood cells in blood, has been used as a measure of avian condition. We investigated the relationship between hematocrit and condition in a wild, breeding population of adult European Starlings (Sturnus vulgaris), and their nestlings (at 5- and 11-days post hatch). Hematocrit was not ...

We used collection of prey remains, direct observations of hawks with prey, and video cameras at two nests to assess frequency of occurrence and biomass of prey species taken by breeding Cooper's Hawks (Accipiter cooperii) in Victoria, British Columbia, Canada during 1995-2010. Small ([less than or equal to] 27 g) ...

We observed an active nest of the Grey-bellied Hawk (Accipiter poliogaster) in the mixed rainforest of southern Brazil during the 2011 breeding season. The nest was a platform built in the branches of the upper part of a Parana pine (Araucaria angustifolia). The clutch size was two eggs, but only ...

The Red-tailed Hawk (Buteo jamaicensis) is a top predator of upland ecosystems in the Greater Antilles. Little information exists on the ecology of the insular forms of this widely distributed species. We studied movements and resource use of the Red-tailed Hawk from 2000 to 2002 in the montane forests of ...

We report the first description of the nest, eggs, and nesting phenology of the Cozumel Vireo (Vireo bairdi), a passerine species endemic to Isla Cozumel, Mexico. We discovered three nests of this species in 2009. These open-cup nests were woven onto branches and hung beneath forks. Clutch size was 2-3 ...

We installed nest boxes for Thorn-tailed Rayaditos (Aphrastrura spinicauda) and monitored their use in a Monterrey pine (Pinus radiata) plantation in the Maule Region, southcentral Chile. Thirty-four breeding pairs built nests in boxes, of which 75% began laying eggs. Nest establishment began in early September and construction lasted 12.8 [+ ...

We examined support for the hypothesis that abundance of Cerulean Warblers (Setophaga cerulea) increases with percentage of bottomland and upland forest, and decreases with percentage of developed land at a local-habitat scale (within a 250-m buffer) and increases with percentage of all forest at a landscape scale (within a 10-km ...

Population composition of Aechmophorus grebes was investigated in Utah and the occurrence of possible intermediates between Western (Aechmophorus occidenmlis) and Clark's (A. clarkii) grebes was assessed. Individuals with clearly intermediate traits represented an aggregated 6.5% (43 individuals) in the populations investigated while another 7.6% (46 individuals) did not entirely conform ...

We equipped five Black-necked Cranes (Grus nigricollis) with satellite transmitters between February and November 2009 to investigate their migration routes between breeding areas and wintering area at Napahai Marsh (3,260 m asl), China. We identified the Shaluli Mountain region (southwest Sichuan), including Daocheng, Litang, Baiyu, and Xinlong counties as a ...

We placed light-level geolocators on 17 Rusty Blackbirds (Euphagus carolinus) in 2009 to track their migrations from nest sites near Anchorage, Alaska to wintering areas and back. We recaptured three of these birds in 2010 and found they departed breeding areas during the first half of September, spent 72-84 days ...

The winter distribution of neotropical seedeaters (Sporophila spp.) known as capuchinos is poorly known. There are difficulties to understanding their migration patterns: fieldwork is lacking in their wintering areas, their 'eclipse' plumages often make it difficult to identify species, different species share habitats during winter, and there is little or ...

We documented unusual variation in the sequence of primary replacement during the prebasic molt of Rufous Fantails (Rhipidura rufifrons) captured in 2009 and 2010 on Saipan, Northern Marianas Islands. Most captures (62%) followed a typical replacement sequence, starting at the proximal primary (P 1) and proceeding distally to the outermost ...